I’ve lived in Bangkok for a few years, have a thai partner. I’m now on my fourth Thai school, still at the beginner level. I also have a private tutor. The problem is it’s worse than hard labor for me to memorize vocabulary. 10 minutes and I’m ready for a nap. I’m older, but I was like this when I was young, also. I really loved AUA, were you just watch to Thai people talking, no book, no homework. They closed during Covid. I start tomorrow at Rak Thai. Class is five afternoons a week, and I will have to be accountable to memorize a vocabulary from the book each day. Tones and the alphabet are not so bad for me. I went to Everyday Thai, in Sathorn , the teacher moved too fast, and got mad when I couldn’t remember the words, even though I studied for hours every day. The knowledge, in Asok, it’s pretty nice, and one lesson does not depend on the other. However, they have 15 words for each lesson in the book, but the teachers add about 50 more words, which again was too fast for me. I took a sample classes at Duke; they drill the class over and over in about 10 to 12 words each lesson, but they have a waiting list. Rak Thai had an opening, works something like Duke…
you don’t ever have to leave. Extension each year for non OA (required health insurance, visa gotten in your home country) each leaving and reentry gets you a year’s stay, for the first year. For non O, usually obtained in Thailand by first entering on tourist visa–then get 90-day retirement visa, which you then extend each year. You don’t have to leave the country, but if you do, get a reentry permit to preserve your visa. 
As other said, it’s a good option if you have the money and you’re well under 50. Myself, I’ll be on my fifth extension of a non-O retirement visa. Not that much trouble to get, I have to do 90 day reports and get reentry permits, but elite still requires a 90 day report. Expedited passport control and limousine service from Bangkok airports are not of that much value, you can pay for these things if you need them.
Unique car and motorbike driving licenses if you drive both. If you have a current license from your country and an international driving permit attached to it, that is easiest. You will need the residents letter we speak of here about bank accounts. I use an agent, fat boys in Bangkok, for my driving license. You can do it yourself, but I find the process bewildering.